Since its introduction in 1992, intracytoplasmic sperm injection (ICSI) has made the treatment of severe male infertility possible, particularly that of azoospermia, both secretory and secretory. Some azoospermic subjects have a pathological development of the seminal pathways, and in particular of the vas deferens and/or ejaculatory ducts. A large part of these subjects show, like patients affected by cystic fibrosis, mutations in the cystic fibrosis transmembrane regulator (CFTR) gene. Some of these azoospermic subjects are indeed paucisymptomatic fibrosis cystic patients who bear the risk of transmitting cystic fibrosis, seminal pathways alterations and, possibly, renal malformations to their offspring. We describe a case of an infertile patient with right CUAVD and azoospermia previously treated by crossed epididimovasostomy in the absence of any genetic and an adequate anatomic evaluation. He was then found to be CFTR mutation positive and without demonstrable spermatozoa in the vesicular fluid despite ultrasound evidence of left ejaculatory duct obstruction. During the second TESA-ICSI cycle an ongoing pregnancy was obtained. An extensive genetic examination for CFTR mutations and a through anatomical study is, therefore, mandatory in these patients to select the most appropriate treatment in CFTR mutation positive and negative CUAVD patients.